The invention relates to the determination of the pitch of a wave, and, more particularly, to the accurate determination and indication of pitch using a compact, portable instrument, hereafter sometimes referred to as a pitch meter.
It is important to determine the pitch of a sound in order to tune musical instruments in general, and particularly stringed instruments such as pianos, violins and guitars. It is also important to determine pitch as an aid in the teaching of music and musical skills and in the evaluation of musical performance. A particular pitch is determined by the frequency or number of vibrations per second of the fundamental of a musical tone. A pitch can also be specified by its period which is the reciprocal of its fundamental frequency.
The measuring devices which are presently available for the accurate determination of pitch tend to be complex and cumbersome. Those which are simple and easy to use tend to be inaccurate. Thus, although tuning forks can be used to establish the pitch of a note, their use involves a cumbersome trial and error procedure and human judgment. In addition, there is no clear indication of the extent of the deviation between the fundamental frequency of a fork and that of a tone under consideration.
Accordingly, it is an object of the invention to make an evaluation of pitch with a high degree of accuracy and without resort to complex and cumbersome techniques or to techniques that require human judgment. A related object is to realize a portable meter and simple technique for the determination of musical pitch.
Another object of the invention is to realize in a simple and accurate way an indication of the extent of the departure of the fundamental pitch of a received tone from the pitch of the closest tone in a given list of standard tones.
Another object of the invention is to allow the user the option of adjusting over a narrow range the frequencies associated with standard tone names. For example, the standard tone associated with the name A can be adjusted over the range 430 to 450 Hz.
A further object of the invention is to determine the fundamental frequency of an incoming acoustic wave without interference and spurious indication because of the presence of harmonics.
Still other objects are to achieve wide range, fast acting pitch detection and display without the need for pre-adjustment, or of prespecification of a note or note range, or of calibration of the detector or of other human intervention in the measuring process. This allows the successive determination and display of the pitches of tones presented in sequence as in a performed musical passage.